1. Field of the Invention
The present invention relates to apparatus for detecting a cracked substrate, and more particularly to a substrate detection system, which detects the intact status of each substrate during its delivery by a conveyer.
2. Description of Related Art
During the fabrication of a substrate, for example, TFT-LCD (Thin Film Transistor Liquid Crystal Display), the surface cleaning of the substrate is quite important so that the desired high quality and high stability standards can be obtained.
During fabrication, a substrate may crack due to a variety of factors. When the delivery apparatus, for example, conveyer keeps, delivering this cracked substrate, the substrates delivered subsequently may also crack, and further result serious loss.
Please refer to FIG. 1A. FIG. 1A is a schematic drawing showing the detection of a cracked substrate according to the prior art. FIG. 1B is a schematic top plain view of a part of FIG. 1A. According to this conventional design, a conveyer 92 with a sensor 93 completes the detection of the cracked substrate. As the conveyer delivers the substrate 91 and the position of the substrate 91 is set, the sensor 93 will locate below the substrate 91. At the same time, the sensor 93 starts to detect the existence of the substrate 91, and further detect the cracked status of the substrate 91.
According to the aforesaid detection method, the sensor 93 detects only one specific part of the substrate 91. If the location of the cracked area of a cracked substrate 91 that has been positioned in the detection position does not pass through the top side of the sensor 93, the sensor 93 cannot detect the cracked status, and cracked substrate 91 will pass the detection, thus a detection error occurs.